NSDate
一般应用
NSDate *date = [NSDate date];
NSDate *date = [NSDate dateWithTimeIntervalSinceNow:10];
NSString *str = [date description];
NSDate *date2 = [str dataUsingEncoding:NSUTF8StringEncoding];
[NSDate distantFuture];
[NSDate distantPast];
时间比较
[date1 earlierDate:date2];
[date1 laterDate:date2];
[date1 timeIntervalSinceDate date2];
BOOL isOK = [date1 isEqualToDate: date2];
获取NSString时间,输出与现在的时间差
NSTimeZone *zone = [NSTimeZone systemTimeZone];
NSInteger interval = [zone secondsFromGMTForDate: [NSDate date]];
NSDate *localeTime = [[NSDate date] dateByAddingTimeInterval: interval];
NSDateFormatter *dateFormatter=[[NSDateFormatter alloc] init];
(格式必须相对应)
[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm"];
NSString *timeStr = [data.time substringToIndex: 16];
NSDate *examTime = [dateFormatter dateFromString:timeStr];
NSLog(@"%f",[examTime timeIntervalSinceDate:localeTime]);